Shocking...just Shocking??

[Denny01]

7 minutes ago, canderson said:

One wonders whether someday one could cruise on a ship whose hotel power was clean enough to begin with not to cause issues for typical shoreside devices.  The problems at the root of the overheating and fires would never be tolerated anywhere else.

 

There have been two different faults identified in various papers and quotes here at CC: imbalance of voltage and noise that was blamed on SCR noise from propulsion power.  The former should be detected and force the offending circuit open, and the latter ... what can I say but wow.  If the spikes are bad enough and continuous enough to take out MOVs, I wouldn't want my gear plugged into it at all since protection against it isn't permitted. 

I’m sure thats all an easy fix. How about just following a few simple requests of what not to smuggle on….concentrate on sneaking booze.

 

den

[chengkp75]

13 minutes ago, Denny01 said:

In other words, if its a 2-prong device, even if you plug it into a surge-protection connection, it doesnt get the benefit. 

Well, surge protection comes from upstream, so if you plug a two prong device into a surge protector, yes it will get protection from surges, because the surge protector is between the device and the surge.

[markeb]

31 minutes ago, cangelmd said:

Like the one with the pigtail shown before?

 

More like this

 

 

https://smile.amazon.com/Charger-Sacrack-Charging-Station-Portable/dp/B09GJXVHVK/?_encoding=UTF8&pd_rd_w=jpykF&content-id=amzn1.sym.8cf3b8ef-6a74-45dc-9f0d-6409eb523603&pf_rd_p=8cf3b8ef-6a74-45dc-9f0d-6409eb523603&pf_rd_r=4WK34KKX3BVACQ6J7M60&pd_rd_wg=dxFJv&pd_rd_r=1d0b28c8-cd11-4c9a-8d53-96ada4e1bc51&ref_=pd_gw_ci_mcx_mi&th=1

 

This one won't charge a laptop; there are versions that have a 65W USB C/PD port that will charge USB C laptops (a lot of Dells, for instance) as well as an iPad Pro and other electronics at the same time.

 

I have a 4 port USB C charger that looks like this, with 2 USB C ports and 2 USB A 3.0 ports. I can charge an iPhone and an iPad Pro at the same time, and and two other lower wattage electronics. I have chargers for my camera batteries that charge on the USB C port (no need to carry an adapter).

 

 

They all have standard two prong plugs, just like laptop bricks. 

 

The outlet with the pigtail has USB 1.0/1.1 plug. They are very low amperage and will be horribly slow to charge most USB devices. And many if not most newer USB devices charge on USB C as well, which is even faster.

[canderson]

1 minute ago, Denny01 said:

I’m sure thats all an easy fix. How about just following a few simple requests of what not to smuggle on….concentrate on sneaking booze.

 

den

How about I'm not suggesting otherwise, Den?  C'mon.

 

But I'm also suggesting that the issues that occurred were preventable, and future design should take such things into account.  Based upon amazing things that @chengkp75 and some white papers report about hotel power, everything you plug in is already at some risk.

 

I've spent WAY to many days in electrical certification test labs working on CE compliance issues to know that I don't want to run susceptibility testing of my own gear by plugging it in while on vacation.

 

What may prove more .. er .. shocking .. is that MOVs are built INTO some of the plug-in supplies that supply DC to power our gadgets.

 

[Denny01]

7 minutes ago, canderson said:

How about I'm not suggesting otherwise, Den?  C'mon……

Sorry, you are exactly right and I was off base on that one. Just get too wrapped up when we get into this…I can’t be seen with a wrinkle. Enough. 

 

I get too cheeky at times. I stepped away from CC for a while when I realized I was responding with too much jerk.

 

Den

 

Edited August 14, 2022 by Denny01

[chengkp75]

22 minutes ago, canderson said:

One wonders whether someday one could cruise on a ship whose hotel power was clean enough to begin with not to cause issues for typical shoreside devices.  The problems at the root of the overheating and fires would never be tolerated anywhere else.

 

There have been two different faults identified in various papers and quotes here at CC: imbalance of voltage and noise that was blamed on SCR noise from propulsion power.  The former should be detected and force the offending circuit open, and the latter ... what can I say but wow.  If the spikes are bad enough and continuous enough to take out MOVs, I wouldn't want my gear plugged into it at all since protection against it isn't permitted. 

Your impressions are not quite right.  Yes, noise from SCR drives can cause MOV's to fail, but not because there is a voltage spike of sufficient intensity or duration.  None, repeat none, of any electronics that are part of the ship are protected by surge protectors, as they are not needed.  This is true for all the computers used onboard, the navigation equipment, the radio equipment, the POS cash registers, and the engine automation that keeps the ship running.  As for the "imbalance of voltage", not sure what you mean by this.  But, the noise from the SCR drives, leads to the same failure of the MOV's as all other failures of surge protectors on ships, reverse voltage.  What is reverse voltage?  The MOV's used in surge protectors are designed to see a high voltage in the "hot" leg of the wiring, and low voltage in the neutral and ground.  These MOV's bridge between the hot and neutral legs and ground, providing a path for current if the voltage on the hot or neutral leg are high enough.  If the MOV senses a higher voltage on the ground, then is present at the hot or neutral legs, they will burn out, or go into "thermal runaway" and melt down.  Now, how is it possible for the ground (which we all know is "ground") to be at a higher voltage than the hot or neutral?  On a ship, the neutral and ground are not at the same voltage (60v hot to ground, and 60v neutral to ground), so that there is no possibility of the neutral current being carried in the ground conductor (which is the hull).  Current in the hull can lead to corrosion of hull and fittings, so the condition of all wiring circuits is monitored with relation to ground.  Now,  if a 480v motor goes to ground due to insulation failure, the ground now has 480v on it, and the hot/neutral have 60v, so the MOV sees "reverse voltage", and melts down.  This is why I call a surge protector the "silent killer" on ships, since a surge protector that is working perfectly fine, can catch fire from a cause entirely outside your control, and possibly at the other end of the ship.

 

There are surge protection devices made for marine electrical systems, but they are very expensive, and for normal, commercial use they are not needed.  Typically, only the Navy uses them.

 

Why aren't surge protectors needed on ships?  What are the two most common causes of voltage surges on land?  Lightning and transformer shorts.  With the ship's electrical system completely divorced from the "ground" (hull), lightning that strikes the ship passes harmlessly through the hull to the ocean.  I've been on several ships struck by lightning, and have never had any electronics fail, and never have had surge protection.  Land transformers go from 10k volts to the 220v that comes into your house.  If that transformer shorts, you get 10k volts to your computer.  On a ship, the 10k volts that are generated, are stepped down to 440v in one transformer, then to 220v in a completely separate transformer, and finally to 110v in a third transformer.  So, to get more than 600 volts at the outlet in your cabin (the typical clamping voltage of a consumer surge protector), you would have to have a simultaneous failure of 3 transformers.  Ships simply don't see the types of voltage surges that happen on land.

[chengkp75]

17 minutes ago, canderson said:

Based upon amazing things that @chengkp75 and some white papers report about hotel power, everything you plug in is already at some risk.

Don't think I ever said that, unless you are plugging a surge protector in.  I've plugged my laptop into ship's power for decades, and even had it plugged in and running when the ship was struck by lightning.

Edited August 15, 2022 by chengkp75

[chengkp75]

18 minutes ago, canderson said:

What may prove more .. er .. shocking .. is that MOVs are built INTO some of the plug-in supplies that supply DC to power our gadgets.

It is not the MOV that is the problem, it is the way it is connected.  Those DC power supplies don't place the MOV across hot/neutral to ground, just from hot to neutral, and are used to shut off the output power when the input voltage gets too high (voltage limitation, which is frequently advertised as surge protection).

[canderson]

33 minutes ago, chengkp75 said:

It is not the MOV that is the problem, it is the way it is connected.  Those DC power supplies don't place the MOV across hot/neutral to ground, just from hot to neutral, and are used to shut off the output power when the input voltage gets too high (voltage limitation, which is frequently advertised as surge protection).

I've seen 3 conductor AC>DC supply designs that use MOVs in both common mode (to ground) and differential mode (line to 'neutral').  So while not an issue for my Toshiba, I have a Dell notebook whose 3-wire "grounded" supply could in fact create an issue.

 

For whatever reason, there are still 3-wire supplies around, perhaps designed as a workaround to the simpler double-insulated design.  

[Bobbiegentry]

3 hours ago, chengkp75 said:

These little gems are some of the worst for fires.  Even if you have brought it on before, and the cabin steward doesn't say anything about it, because they don't know, or don't want to lose their DSC by ticking you off, doesn't mean it isn't a danger.  Even a brand new, working perfectly surge protector, when plugged into the ship, can catch fire due to something completely out of your control, and at the other end of the ship.  On another thread, I discussed this problem, and another poster reported that that was just what happened.  They plugged the Belkin in, had nothing plugged into it, and it started to smoke and get hot.  If left, it would have melted and caught fire.

Actually, a surge protector cannot "damage the ships electrical system" in any way, the only danger is to the surge protector itself, which can catch fire.

The bathroom outlets, marked "razor only" are limited to 40 watts of power, so only an electric razor, or an electric toothbrush or waterpik would work.  These are fused, so if you overload it, it requires the electrician to dismantle the whole light fixture to replace the fuse.

Thank you, Sir. 

[canderson]

@chengkp75

 

If a 480V motor shorts 480 to ground, surely that would be detected and the circuit opened in milliseconds? 

 

More to the point, how is 480 propulsion current related to hotel power?  It would be fascinating to see an overview diagram.  Surely hotel power isn't stepped down from the 480?  One could easily imagine instead two separate power sources sharing common drive, but as separate electrically.  While sharing a common ground, power issues on one wouldn't show up on the other. 

 

I'm picturing two parallel generation systems on land, sharing a common ground (the ship's hull, in this case) but nothing else.  

 

Or is hotel power really directly derived from the higher voltage propulsion power?  If so, one would think that propulsion switching noise would be at a frequency high enough that it would appear at a negligible level on the other side of a transformer large enough to do the job.

 

The SCR business is from an email conversation someone here had with a marine engineer, and pointed to in the thread here somewhere.  Assume they're used back to back for AC power control?  Zero cross switching deals with noise issues if there are any, but it sounds like your experience indicates that problem may have been overstated. 

 

You also said something else that, if I read it correctly, is really fascinating.  Please tell me if I understand correctly:

 

Leaving out 240V, which you didn't mention, but is likely comparable.. 

 

Differential nominal between "line" and "neutral" runs around 120V, but each is really 60V to hull ground common mode?  There's typically 60V between the "neutral" line and the hull?  I take it then that all breakers aboard break both sides?  I would hope so!

[canderson]

2 hours ago, Denny01 said:

I get too cheeky at times.

 

Den

 

To your credit, not very often!

[chengkp75]

7 hours ago, canderson said:

If a 480V motor shorts 480 to ground, surely that would be detected and the circuit opened in milliseconds? 

If a motor insulation fails, there will be a path from one conductor to ground, and if it results in a serious enough ground fault, then the breaker will fail.  However, it could be a partial failure of the insulation, resulting in a lower current flow than the breakers are rated for, but which would still introduce enough current to start electrolysis.   However, since this is the only path from the ship's wiring system to  ground, there is no interference with the wiring system, merely the introduction of electrolysis of metals in the hull.  This is monitored by a "ground fault meter", which is a milliamp meter that is connected with a resistor between line and ground, providing the return connection from ground to the system.  If current is detected, the meter indicates, and the engineers start looking for the circuit, and then the device that is grounded.

 

7 hours ago, canderson said:

More to the point, how is 480 propulsion current related to hotel power?  It would be fascinating to see an overview diagram.  Surely hotel power isn't stepped down from the 480? 

There is only one power source on the ship, all generators generate 10k volt AC power, and feed a common bus.  This bus supplies propulsion, hotel, and engineering power.  And, as I said, wherever needed, the 10k volt power is stepped down in steps from 10k to 440v, 440v to 220v, and 220v to 110v.  And, the propulsion motors, as well as the thrusters, and AC chiller motors are 10k volt motors, not 440v.  Most major motors onboard (pumps, compressors, fans, laundry machines, galley equipment like ovens, ranges, refrigerators) are 440v as well.

 

7 hours ago, canderson said:

The SCR business is from an email conversation someone here had with a marine engineer, and pointed to in the thread here somewhere.  Assume they're used back to back for AC power control?  Zero cross switching deals with noise issues if there are any, but it sounds like your experience indicates that problem may have been overstated. 

The SCR drives are 3-phase, as is all equipment that is 440v and above, so you have a bridge of 6 SCR's to control the frequency of the output AC.  It's been a while since I did a deep dive into the circuitry, but I believe that zener diodes are used to filter noise spikes to neutral ( the generators are star wound with a neutral point, and the motors and everything else are delta wound).  I don't know enough about semi-conductor construction to know, but I believe that MOV's have a limited amount of joules they can shunt, and even small overvoltages, over small periods (noise spikes), can "build up" in the MOV and cause eventual failure.

 

7 hours ago, canderson said:

Differential nominal between "line" and "neutral" runs around 120V, but each is really 60V to hull ground common mode?  There's typically 60V between the "neutral" line and the hull?  I take it then that all breakers aboard break both sides?  I would hope so!

That is correct.  There is 60v between neutral and ground.  This allows for determination of a ground fault on the neutral wiring, to prevent electrolysis.  And, yes, all breakers are two pole.  I just got into this with another poster on another thread, who said the "safest power strip for cruise ships has a 15 amp breaker and no surge protection".  I countered with the safest power strip is as he described, but with a two pole breaker in the power strip, as consumer power strips only break the hot leg, and not the neutral.  He didn't understand the nature of the "floating ground" (not connected to neutral).  All of the power strips I've used on ships over the last decades have been "European" ones (rated 220v, but that's not important), that have a two pole breaker in them for just this reason.

 

We also cannot use things like household or commercial UPS, since these look for 120v hot to ground as the "normal" condition, and when plugged into a ship that is producing 120v AC power (hot to neutral), but with only 60v hot to ground, it immediately goes into "power failure" and "battery mode".  We have to use special marine UPS that recognize the floating ground.

Edited August 15, 2022 by chengkp75

[Redtravel]

Had power plug taken on Celebrity once.  Had to report to the luggage deck to claim. It’s used for medical devices. Got it back after explaining.  No other cruise line has taken my power plug away.   All it annoying.  In June I sailed on X. Brought a multi outlet device with no cord.  It wasn’t taken away.  

[PaperSniper4]

Okay, I feel like I am now ready for taking my examination to certify me as a Master Electrician.....seems like we've beaten this dead horse beyond any chance of resuscitation!😉

 

Lots of great information above.

 

 Doug

[miched]

14 hours ago, chengkp75 said:

 

The bathroom outlets, marked "razor only" are limited to 40 watts of power, so only an electric razor, or an electric toothbrush or waterpik would work.  These are fused, so if you overload it, it requires the electrician to dismantle the whole light fixture to replace the fuse.

I have tried to use a waterpik  many times and it would kick out after a few seconds.  It is a GFI type outlet and can be reset by pushing the button.   
 

Tried using the outlet to charge my razor and that didn’t work either as the plug contains the transformer that is rather heavy and it falls out of the outlet that is in the ceiling.   I guess it would work for a razor that had a different charge system. 
 

Happy cruising 🌊🚢🌅🇺🇸

Edited August 15, 2022 by miched

[canderson]

@chengkp75

I want to thank you for elaborating on all of this in yet greater detail.  Had no idea the whole thing started from a single 10K 3 phase source, and your very clear 60-G-60 explanation clarified a lot of things as well.  Don't touch the outer conductor when changing light bulbs, right?😳

 

It's a very different world aboard, and the use of a 'megger' now becomes clear as well.  Always wondered about that.

[chengkp75]

46 minutes ago, canderson said:

It's a very different world aboard, and the use of a 'megger' now becomes clear as well.  Always wondered about that.

Insulation checks are done annually, at minimum, and we start to worry when it gets less than 400 Megohms (.001 milliamp), nowhere near the breaker tripping point.

[Keys Kathy]

On 8/14/2022 at 3:53 AM, KatieDub said:

I never understand the need for a power extender... How many devices are you guys charging 🤪

one computer, 2 Iphones, 2 kindles and 2 portable chargers.

[chengkp75]

13 minutes ago, Keys Kathy said:

one computer, 2 Iphones, 2 kindles and 2 portable chargers.

That's one Schuko (European 220v) plug adapter, and a 6 port USB charging hub.  Still should have one 110v outlet available for the hair dryer.

Edited August 15, 2022 by chengkp75

[Keys Kathy]

8 minutes ago, chengkp75 said:

That's one Schuko (European 220v) plug adapter, and a 6 port USB charging hub.  Still should have one 110v outlet available for the hair dryer.

LOL! I have 4 usb ports on my computer and another 3 outlet hub. I take a 3 socket strip without a surge supressor. 

[markeb]

59 minutes ago, Keys Kathy said:

LOL! I have 4 usb ports on my computer and another 3 outlet hub. I take a 3 socket strip without a surge supressor. 

 

I'm curious, too. You're the only person on the thread that I remember actually saying what they were charging and I'd like to understand.

 

What are you using the 3 socket strip for? Everything you're carrying, except probably the laptop, will charge on one USB C/A hub without carrying the original charging adapters. There are plenty of portable hubs that will give you two high wattage (25-65W) USB C ports and 3-4 (and sometimes more) USB A ports. That should easily charge two phones and two kindles at the same time from one outlet. The Schuko (type E/F) adapter will give you an extra outlet in the cabin for any of your multivoltage electronics (they pretty much all are) like the laptop and save the space of a power strip. Most phone makers don't even supply adapters anymore. They assume you'll use your old one, or a hub. Even the cables, if supplied, will detach and work on a hub.

 

If it works for you, great, but I'd never do what you're doing. I just carry a USB hub and if travelling internationally, an adapter for the country I'm traveling to.

 

 

[Keys Kathy]

3 minutes ago, markeb said:

 

I'm curious, too. You're the only person on the thread that I remember actually saying what they were charging and I'd like to understand.

 

What are you using the 3 socket strip for? Everything you're carrying, except probably the laptop, will charge on one USB C/A hub without carrying the original charging adapters. There are plenty of portable hubs that will give you two high wattage (25-65W) USB C ports and 3-4 (and sometimes more) USB A ports. That should easily charge two phones and two kindles at the same time from one outlet. The Schuko (type E/F) adapter will give you an extra outlet in the cabin for any of your multivoltage electronics (they pretty much all are) like the laptop and save the space of a power strip. Most phone makers don't even supply adapters anymore. They assume you'll use your old one, or a hub. Even the cables, if supplied, will detach and work on a hub.

 

If it works for you, great, but I'd never do what you're doing. I just carry a USB hub and if travelling internationally, an adapter for the country I'm traveling to.

 

 

I guess I am just too lazy to change things. I have a "cruise" drawer, and just pull out the same stuff I had last time. One thing you have to be aware of, is some ships are killing the power when you leave the room, so things are not charging.

[markeb]

6 minutes ago, Keys Kathy said:

I guess I am just too lazy to change things. I have a "cruise" drawer, and just pull out the same stuff I had last time. One thing you have to be aware of, is some ships are killing the power when you leave the room, so things are not charging.

 

That may be part of the difference. Mine is a 4 X 6 "travel bag", and its contents have changed over the years. But it's small, light weight, and takes care of everything wherever I'm traveling. I just add the right adapter if I'm going internationally (or the E/F adapter for a cruise ship).

 

But you can totally charge what you're carrying without a power strip by using a USB charging hub. And I get the impression a lot of people are carrying power strips/outlet extenders when they really just need a low power charging hub and the right cables.

[Keys Kathy]

3 minutes ago, markeb said:

 

That may be part of the difference. Mine is a 4 X 6 "travel bag", and its contents have changed over the years. But it's small, light weight, and takes care of everything wherever I'm traveling. I just add the right adapter if I'm going internationally (or the E/F adapter for a cruise ship).

 

But you can totally charge what you're carrying without a power strip by using a USB charging hub. And I get the impression a lot of people are carrying power strips/outlet extenders when they really just need a low power charging hub and the right cables.

What you say is true, especially now that they are adding USB chargers at the base of lamps etc. I guess I need to rethink my stuff, after all it's not the 90's anymore.